The present invention relates to pressure sensors, and more specifically, to a pressure sensor comprising a housing and a connector case, storing in the interior thereof a sensor element for sensing pressure, a substrate having an amplifying thick-film board circuit, a lead connecting the sensor element and a terminal, a shield plate with a penetrating condenser, a terminal holder and a terminal, and a water-proof o-ring and so on.
In the prior art, a pressure sensor as shown in FIG. 13 was known. FIG. 13A is an explanatory cross-sectional view of a prior art pressure sensor, FIG. 13B is an explanatory exploded schematic view of the same pressure sensor, and FIG. 13C is an explanatory cross-sectional view of the shield member used for said pressure sensor.
This pressure sensor comprises a housing 1' and a connector case 9', and in the interior of a container formed by said housing 1' and the connector case 9', a sensor element 2' for sensing pressure, a substrate 3' having an amplifying thick-film board circuit, a lead 4' for connecting the sensor element 2' and a terminal 72', a shield member 5' having a penetrating condenser 51', a terminal holder 71' and a terminal 72', a water-proof o-ring 8', and so on are stored. The housing 1' and the connector case 9' are directly staked and connected together.
The housing 1' is a metallic case where the sensor element 2', the substrate 3', the shield plate 5', the connector case 9' and the like are assembled. The sensor element 2' comprises of a header 21', a seat 22' and a sensor chip 23', and mounted to the housing 1'. Further, the sensor chip 23' is formed to have a c-shaped cross section, which is set to deform when receiving a pressure of liquid from a hole formed on the housing 1' (not shown), and outputs an electric signal corresponding to the degree of deformation. The header 21' and the seat 22' support the sensor chip 23', and fixes the same to the housing 1'.
The substrate 3' is formed to have an octagonal shape, comprising an amplifying thick-film board circuit (not shown) for amplifying a weak signal from the sensor element 2', and the lead 4' is a wire including a power and a ground for transmitting the electric signal amplified by the amplifying thick-film board circuit to the terminal 72'.
The penetrating condenser 51' is for removing an electromagnetic noise intruding through the terminal 72' from the exterior thereof to the shield member 5', which is fixed to a hole formed on the shield member 5'. The shield member 5' is formed to have a c-shaped cross-section as is shown in FIG. 4(c), and fixed to the housing 1' by injection. Said member works as the exterior electrode of the penetrating condenser 51', and by being connected to the housing 1', removes the electromagnetic noise and the like from the terminal 72' to the exterior through the housing 1'.
The terminal holder 71' supports the terminal 72' by an insert mold, so as to withstand the connecting and removing movement of the connector. The terminal 72' is connected to the lead 4', and inputs or outputs the output signal from the power source, the ground and the sensor element 2' with the exterior.
The water-proof o-ring 8' is for preventing the intrusion of water or moisture and the like from the exterior, and is mounted on the portion for staking the housing 1' and the connector case 9'.
The connector case 9' is a case made of resin where the terminal 72' is inserted and fixed, which holds the shield plate 5' and the terminal holder 71'.